Endoscopic instrument system having reduced backlash control wire action

ABSTRACT

An endoscopic instrument has a control member, a portion of the member having an outer surface with a non-circular cross-sectional shape. The non-circular cross-sectional shape may be provided to the control member by providing peripheral projections or fins along the length of the portion or by providing the periphery of the portion with a polygonal shape. Where fins are used, the fins are preferably quite small and only have a minimal effect on the fluid flow cross-sectional area between the interior of the endoscope instrument shaft and the central control member. The resulting instrument has significantly reduced backlash in end effector assembly manipulation, while maintaining adequate fluid flow in the endoscope shaft. According to a second embodiment of the invention, a portion of the interior of the shaft of the endoscopic instrument has an interior surface having a non-circular cross-sectional shape by the inclusion of a plurality of radially spaced and inwardly directed ribs or by being polygonally shaped. The resulting endoscopic instrument likewise reduces the backlash experienced in operating the distal end effector assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/309,993, filed on Dec. 4, 2002 now U.S. Pat. No. 6,840,900; which isa continuation of U.S. patent application Ser. No. 09/716,710, filed onNov. 20, 2000, now U.S. Pat. No. 6,537,205; which is acontinuation-in-part of U.S. patent application Ser. No. 09/418,246,filed on Oct. 14, 1999, now U.S. Pat. No. 6,454,702, the entiredisclosures of which are all hereby incorporated by reference.

FIELD OF THE INVENTION

This invention relates broadly to surgical instruments. Moreparticularly, this invention relates to an endoscope and endoscopicsurgical instruments adapted to be extended into a channel of theendoscope.

BACKGROUND OF THE INVENTION

At the present time there are many instruments made for use inendoscopic medical procedures. Typically, endoscopic instruments arelong and flexible cylindrically tubular devices with manually operatedhandles at their proximal ends and tissue-manipulative cutting,grasping, injecting, or cauterizing components at their distal ends.These distal devices, also called effector-end assemblies, after beingmoved to the intended treatment site by means of the endoscopicinstrument tube, are operated by a control member, such as a wire. Thecontrol member typically may be pushed as well as pulled, to allowmotion of the control element, and therefore operation of the distaldevice, in both directions. For example, the control member may allow aphysician to close and open a pair a forceps by moving one of theforceps jaws relative to the other, which may be fixed. Alternatively, abiopsy or other needle may penetrate tissue by being inserted into suchtissue at the distal end of the endoscopic instrument tube by pushingthe control member distally by means of the control member's proximalhandle. Further, a snare may be included as the effector-end assembly asdisclosed in commonly assigned U.S. Pat. No. 6,517,539 entitledPolypectomy Snare Having Ability to Actuate Through Tortuous Path,” thedisclosure of which is hereby incorporated by reference.

The endoscopic instruments are introduced into a flexible endoscopewhich is inserted into the patient through a natural orsurgically-created opening. The endoscope includes an elongate portiondefining several lumens therethrough and a proximal handle for directingthe elongate portion. At least one lumen is provided with an opticalimaging system (e.g., a scope), and several lumina or “working channels”are typically provided for extending endoscopic instrumentstherethrough. The working channel of the endoscope typically consists ofa PTFE-lined cylindrical tube passing from the proximal (handle) end ofthe endoscope to its distal (working) end. Working channels aretypically 2 to 4 millimeters in inside diameter.

During the medical procedure, the doctor passes one or more endoscopicinstruments through the working channel or channels in order tomanipulate the tissue being visualized by the optical system of theendoscope. In the course of positioning the distal effector endassembly, usually the doctor must repeatedly manipulate the distal endof the instrument by manually pushing and pulling on the proximalportion of the tubular shaft of the endoscopic instrument near where theshaft enters the handle of the endoscope. After the end effectorassembly has been placed at the treatment site, the end effectorassembly must similarly be manipulated or effected using the controlelement. For example, the physician may wish to open or close a forceps,or insert a needle into tissue at the distal end of the endoscopicinstrument and then withdraw the needle without moving the entiretubular shaft of the needle instrument.

The view through an endoscope is highly magnified when seen on the videomonitors typically used for these procedures; a field of view that maybe a few millimeters across would be enlarged to several inches on thevideo screen. Accordingly, the instrument must be moved very preciselyin very small increments in order to approximate and treat the tissuebeing visualized. In fact, many times, the doctor must position thedistal tip of the endoscopic instrument within a fraction of amillimeter of the desired location in order to achieve desired results.However, because of friction and backlash in the way the instrumentpasses through the endoscope, achieving this level of accuracy isdifficult. For example, an endoscope several feet long may be positionedin the colon of a patient with the distal end of the endoscope tightlyreflexed to visualize a particular area of the ascending colon. In sucha position, the endoscope is bent into a very sinuous shape in multipleplanes. Since the outside diameter of the endoscopic instrument issignificantly smaller (e.g., 2.2 mm) than the inside diameter of theworking channel (e.g., 3.2 mm), a large clearance space exists betweenthe instrument and the channel. Likewise, there is a discrepancy betweenthe outside diameter of the control member in comparison with the insidediameter of the endoscopic instrument tubular shaft. The outsidediameter of a control member may be as small as 1 mm, while the insidediameter of the endoscopic instrument outer tube may be approximately 2mm.

When the instrument is pulled back, the tension on the instrument causesthe instrument to be pulled taut, and the instrument naturally assumesthe shortest path through the working channel. When the instrument ispushed forward, friction causes it to assume the longest path throughthe channel (that is, the shaft of the instrument must “fill” theworking channel before the distal end of the instrument begins to move).As a result, quite a bit of backlash (lost motion) is experienced by thedoctor when the doctor tries to manipulate the distal end of theinstrument. If it is necessary to pull the tip back a bit, the backlashmust first be pulled out before the distal end can be retracted. If thedoctor pulls the instrument back a little too far, the doctor must thenpush it several millimeters forward before there is any motion at all atthe distal end. During this manipulation, the endoscopic instrumentalternately assumes the longest-path and shortest-path positions withinthe working channel of the endoscope.

The situation with regard to the control member is analogous. As thecontrol member is moved distally and proximately vis-à-vis the outertube of the endoscopic instrument, the control member is respectivelyforced to fill the instrument tube, or be pulled taut, before thedesired movement of the end effector assembly takes place. In both themovement of the endoscopic instrument through the working channel andthe movement of the control member within the endoscopic instrument tubeto operate the end effector assembly, it is desirable to minimize lag,or backlash. If this backlash can be reduced or eliminated, themanipulation of the distal end of the endoscopic instrument as a whole,or the operation of the device at the distal end of the endoscopicinstrument operated by the control member, can be made much easier andmore responsive, and the doctor can achieve his desired positioning ordevice operation more easily, rapidly, and precisely. In particular, areduction in the backlash experienced in operating the end effectorassembly with the control member would increase the precision ofsurgical techniques possible with the endoscopic instrument. However,this is not a simple problem to overcome for several reasons.

The backlash situations described above could possibly be reduced orsubstantially eliminated if the clearance between the outside of thecontrol member and the inside of the tubular shaft of the endoscopicinstrument were reduced. However, this is not a practical solution,because it is often necessary to inject fluid (or to operate suction)through the annular space between these two structures. If the controlmember were to substantially fill up the space within the tubularcasing, the backlash would be reduced, but there would be greatlyreduced ability to conduct fluid through the working channel around theinstrument. In fact, because of the nature of fluid flow, as the aspectratio of the annular clearance space (the ratio of the thickness of thefluid channel to its circumferential length) becomes small, theimpedance to fluid flow grows disproportionately to the reduction incross-sectional area of the fluid passage.

In addition, as the diameter of the control member approaches the insidediameter of the tubular casing, the area of contact between theinstrument and the working channel becomes larger. This increase incontact area between these parts results in an increase in frictionaldrag on the control member when the doctor attempts to move it relativeto the tubular shaft.

SUMMARY OF THE INVENTION

The present invention provides an endoscopic system with little or nobacklash, or lag, when manipulating an outer tube of an endoscopicinstrument relative to an endoscope working channel and/or a controlmember of the instrument relative to the outer tube containing suchcontrol member, while maintaining an open area therebetween forpermitting fluid flow and/or relative movement without excessivefriction.

An endoscopic system is provided where either a portion of theendoscopic instrument shaft or a portion of the control member isprovided with a non-circular cross-section.

Generally, an endoscopic instrument includes an elongate flexibletubular member having proximal and distal ends, a control member havingproximal and distal ends and extending through the tubular member, anend effector assembly coupled either to the distal end of the controlmember, or the distal end or both the control member and the distal endof the tubular member, and a handle means for moving the control memberrelative to the tubular member to operate the end effector assembly.

According to a first embodiment of the invention, at least a portion ofthe elongate control member of the endoscopic instrument has an outersurface having a non-circular cross-sectional shape. The non-circularcross-sectional shape may be provided to the portion of the controlmember by radially spacing a plurality of fins, ridges, lands, or otherprojections about the periphery (exterior) of the portion, or byproviding the portion with a polygonal cross-sectional shape. Where finsor ridges are provided, they can be quite small and will only have aminimal effect on the fluid-flow cross-sectional area between the shaftof the endoscopic instrument and the control member. Thus, the resultingendoscopic instrument will have significantly reduced backlash ineffector end assembly operation, while maintaining adequate fluid flowin the lumen of the tubular instrument shaft. In addition, the fins orcorners of the polygonal shape provide few and relatively small contactpoints so that the control member may be easily moved within the lumenof an endoscope instrument shaft. The fins or ridges on the controlmember, or other non-circular outer shape, may be imparted by the use ofa die during extrusion, the die having a shape complementary to thatdesired in the control member.

According to a second embodiment of the invention, an instrument,preferably designed for use via insertion in an endoscope workingchannel, is provided having a proximal handle, and an elongate flexibledistal portion with an outer tubular shaft having a lumen therethrough,within which is a longitudinally extending control member. The outertubular shaft, with the lumen therein along its length, includes asubstantial portion wherein the inner lumen of the outer shaft has anon-circular cross-sectional shape. The non-circular cross-sectionalshape can be provided to the lumen of the shaft by providing theinterior surface of the shaft with a plurality of radially spaced andinwardly directed ribs or other projections, or by providing theinterior surface of the instrument shaft with a polygonal shape. Theribs can be quite small and will only have a minimal effect on the fluidflow cross sectional area between the working channel and the endoscopicinstrument. Therefore, the resulting endoscopic instrument will reducethe control member backlash of the endoscopic instrument whilemaintaining adequate fluid flow in the lumen of the endoscopicinstrument shaft. Additionally, the control member will be easily movedto operate the distal effector end assembly, as there will be few andrelatively small contact points between the two. The outer tubular shaftmay also have a non-circular outer diameter cross-sectional slope inorder to reduce backlash of the endoscopic instrument as a whole with aworking channel.

Under a preferred embodiment of the present invention according toeither alternative discussed above, the control member itself may have alumen for the passage of fluid through the control member, particularlywhen the distal effector end assembly of the endoscopic instrument is ahollow or hypodermic needle. The control member may also have a centrallumen whenever it may be desired to irrigate or provide suction throughthe control member in addition to any fluid flows effected through otherparts of the endoscopic instrument, such as the tubular shaft and theendoscope working channel. Also in a preferred embodiment of the presentinvention, the outer surface of the endoscopic instrument's tubularshaft, or the inner surface of the endoscope working channel throughwhich the instrument is introduced, has a non-circular cross-sectionalshape in order to reduce backlash in the movement of the endoscopicinstrument through the working channel, as described in U.S. patentapplication Ser. No. 09/418,246, filed on Oct. 14, 1999, entitled“Endoscope and Endoscopic Instrument System Having Reduced Backlash WhenMoving The Endoscopic Instrument Within A Working Channel Of TheEndoscope,” the entire disclosure of which is hereby incorporated byreference.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross-sectional view of one embodiment of anendoscopic instrument of the present invention;

FIG. 2 a is an enlarged cross-section across line 2-2 in FIG. 1,according to a first embodiment of the invention;

FIG. 2 b is an enlarged cross-section across line 2-2 in FIG. 1,according to an alternative first embodiment of the invention;

FIG. 3 is a side elevation of an endoscope according to the inventionshown provided with an endoscopic instrument according to the invention;

FIG. 4 is an enlarged cross-section across line 4-4 in FIG. 3,illustrating several working channel-endoscopic instrument systemsaccording to the invention;

FIG. 5 is a plan view of an endoscopic injection instrument with reducedcontrol member backlash according to one embodiment of the invention;

FIG. 6 is a cross-sectional view of the distal end of the instrumentshown in FIG. 5;

FIG. 7 is a radial cross-sectional view of the tubular shaft of theendoscopic instrument of FIG. 6, across line 7-7;

FIG. 8 is a radial cross-sectional view of the tubular shaft of theendoscopic instrument of FIG. 6 across line 7-7, according to analternate embodiment of the present invention;

FIG. 9 is a radial cross-sectional view of the tubular shaft of theendoscopic instrument of FIG. 6 across line 7-7, according to analternate embodiment of the present invention;

FIG. 10 is a radial cross-sectional view of the tubular shaft of theendoscopic instrument of FIG. 6 across line 7-7, according to analternate embodiment of the present invention; and

FIG. 11 is a radial cross-sectional view of the tubular shaft of theendoscopic instrument of FIG. 6 across line 7-7, according to analternate embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIG. 1, an endoscopic instrument 10 for insertion througha working channel of an endoscope is shown. According to a firstembodiment of the invention, the endoscopic instrument 10 includes anactuation handle 12, a tubular coil 14, a jacket 16 provided about atleast a distal portion 18 of the coil 14, an end effector assembly 20,e.g., a biopsy forceps, and a control wire 22. The actuation handle 12typically includes a stationary member 26 and a displaceable spool 28.The stationary member 26 includes a distal throughbore 30, a centralslot 32, and a proximal thumb ring 34. The displaceable spool 28 isslidably disposed on the stationary member 26 and has a cross member 36which passes through the slot 32. The proximal end of the control wire22 is coupled to the spool 28. Operation of the actuation handle 12 isdescribed fully in U.S. Pat. No. 5,228,451 to Bales, which is herebyincorporated by reference herein in its entirety. In brief, longitudinalmovement of the spool 28 within the slot 32 results in operation of theend effector assembly 20 (i.e., the end effector assembly moves betweenopen and closed positions).

Referring now to FIGS. 1 and 2 a, in accord with the first embodiment ofthe invention, the jacket 16 is a low-friction coating or sheath,preferably made from PTFE, extending over at least a distal portion ofthe coil 14. The jacket 16 may be extruded over the portion of the coil,or may be provided as an attachment capable of being provided over anassembled endoscopic instrument. For example, the jacket may be atubular member having a longitudinal slit. The jacket 16 defines several(e.g., five) longitudinal fins 30 radially spaced about the coil. By wayof example, and not by limitation, for an endoscopic instrument intendedto be inserted into an endoscope having a working channel of 3.2 mminside diameter, the jacket 16 is preferably a cylinder 2.2 millimetersin diameter with thin fins (or lands) having a thickness ofapproximately 0.1 mm and extending approximately 0.4 mm out from thecoil surface. Such a construction would almost completely fill thediameter of the working channel of the endoscope (i.e., the radialdimension of the jacket, from the center of the coil 14 out to the endof a fin 30) and is nearly equal to the radius of the working channel),substantially reducing the motion backlash. However, since the fins 30are quite thin, only a small amount of the fluid-flow cross sectionalarea would be sacrificed. Additionally, the number of contact points andsurface area of contact points between the fins and the interior of theworking channel is minimal.

It is also preferable that the fins extend along only a distal portionof the endoscopic instrument rather than along the entire length of theendoscopic instrument. If the fins 30 were to extend to the mostproximal portion of the coil 14, it would be difficult to effect a fluidseal against the shaft of the instrument where the coil enters theendoscope handle. Such a seal is needed if fluid is to be injectedthrough the working channel. Since the majority of the flexing of theendoscope in an endoscopic procedure takes place at the distal portion,where the endoscope is situated inside the patient, the majority ofmotion backlash results from the looseness of the instrument in thedistal portion of the endoscope. Accordingly, it is preferable for thefins 30 to be placed on only the corresponding distal portion 18 of theendoscopic instrument 10 (for example, on the distal 150 cm of a 240 cminstrument) while leaving the proximal portion (i.e., 90 cm) a smoothcylinder. Such an endoscopic instrument would then have greatly reducedmotion backlash when manipulated by the physician, and it would allowsubstantially unimpeded fluid flow through the working channel of theendoscope, while providing an easily sealed-upon surface where theinstrument exits the endoscope handle.

Turning now to FIG. 2 b, according to an alternate first embodiment ofthe invention, the jacket 16 b has a non-circular cross-sectional shapeover the coil 14 such that the cross-sectional shape is generallypolygonal. For example, the jacket 16 b may have a pentagonal shape, asshown. By way of example, and not by limitation, for an endoscopicinstrument intended to be inserted into an endoscope having a workingchannel of 3.2 mm inside diameter, the corners 30 b of the polygonpreferably extend approximately 0.4 mm from the coil surface. Such aconstruction substantially completely fills the diameter of the workingchannel of the endoscope, substantially reducing the motion backlash,yet only contacts the working channel at the corners 30 b. In addition,space is provided between the sides of the jacket and the workingchannel for fluid-flow.

Referring now to FIGS. 3 and 4, an endoscope 110 according to a secondembodiment of the invention is shown. The endoscope 110 includes anelongate tubular portion 112 and a proximal handle portion 114 adaptedto manipulate and direct the distal end of the tubular portion 112. Thetubular portion 112 has a plurality of lumens, with one lumen 142provided for receiving an optical scope or camera device 144 (which maybe built therein), several lumens 146, 148, 150, 152 provided forreceiving control wires 154, 156, 158, 160 extending from the handleportion 114 through the tubular portion 112, and at least one, andpreferably several, working channels 162, 164, 166, 168 for receivingendoscopic instruments 170 therethrough. For example, endoscopicinstruments 10, 10 b according to the first embodiment of the invention(as shown in FIGS. 2 a, and 2 b, respectively) may be provided inworking channels 166, 168. The working channels have proximal openingsin the handle portion 114. Other lumens 172, 174 may be provided forother purposes. Endoscopes are described in general in U.S. Pat. No.5,179,935 to Miyagi, which is hereby incorporated by reference herein inits entirety.

According to the second embodiment of the invention, a portion of atleast one of the working channels 162 is provided with a non-circularcross-sectional shape. The non-circular cross-sectional shape may bemolded into the working channel or more preferably is provided by alow-friction (e.g., PTFE) insert 180 preferably fixed within a distalportion 118 of the working channel 162. The insert 180 includes aplurality of radially spaced and radially inwardly directed longitudinalribs 182. The ribs 182 can be quite small. For example, the ribs 182 maybe approximately 0.1 mm thick and have a radial length of approximately0.5 mm. Therefore, the ribs would have a minimal effect on the fluidflow cross-sectional area between the working channel and the endoscopicinstrument, and also provide relatively small contact points between theworking channel and the endoscopic instrument.

According to an alternate second embodiment of the invention, a workingchannel 164 is provided with a polygonal cross-sectional shape. Thepolygonal cross-sectional shape may be provided to the working channel164 via an insert 182 or may be molded integrally into the workingchannel.

In each of the alternate embodiments, the working channel is adapted toprovide reduced backlash, while maintaining adequate fluid flow in theworking channel around the endoscopic instrument, and minimal contactbetween the endoscopic instrument and the working channel. In eachalternate embodiment, the non-circular cross-sectional shape of theworking channel may extend the entire length of the channel or a portionthereof.

There have been described and illustrated herein several embodiments ofan endoscope and endoscopic instrument system having reduced backlashwhen moving the endoscopic instrument within the working channel of theendoscope. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow, and that the specification be read likewise. Thus, while aparticular biopsy forceps endoscopic instrument has been disclosed, itwill be appreciated that endoscopic instruments having other endeffectors, e.g., scissors, punches, needles, etc., can be provided withthe non-circular cross-section of the invention, as well. Furthermore,while a PTFE has been disclosed for the jacket of the instruments andinsert for the endoscope, other low friction materials can be used aswell. Also, while a particular number of fins and ribs have beendisclosed, it will be appreciated that other numbers of fins and ribscan be used. Alternatively, one or more spiral fins or ribs can beprovided. Furthermore, projections other than fins can be used.Moreover, other polygonal shapes may be used for the jacket over thecoil and the endoscope insert. Also, the coil and/or jacket may besubstituted with another tubular member having a non-circularcross-section. For example, the tubular member may be extruded with apolygonal shape or with fins.

Referring now to FIG. 5, in accordance with an additional embodiment ofthe invention, an endoscopic instrument 210 is shown, which may be usedin an endoscope such as endoscope 110 depicted in FIG. 3 and in axialcross-section in FIG. 4. For example, endoscopic instrument 210 mayoccupy the position of endoscopic instruments 10, 170, or 106 withinworking channels 162, 164, 166, or 168 in FIG. 4. The endoscopicinstrument 210 includes an elongate tubular shaft 212 and a proximalhandle portion 214 adapted to manipulate and direct the distal end ofthe tubular portion 212. The tubular portion 212 has a lumen 218provided for receiving a control member 220 (which may be built therein)and which may be tubular, having a central lumen, if dictated by thedesign of the distal effector end assembly at the distal end of thecontrol member. The endoscope instrument 210 of FIG. 5, an injectionneedle instrument, may be advanced through the working channel of anendoscope in substantially the same manner as endoscopic instrument 10of FIG. 1, a forceps device. Alternatively, a snare may be incorporatedas the distal effector end assembly.

The endoscopic needle 210 may also have ridges or fins along the outershaft 212, or the outer wall of the shaft may otherwise have anon-circular cross-sectional shape, as shown with device 10 incross-sections in FIGS. 2 a and 2 b and devices 10 and 10 b of FIG. 4.The embodiment depicted in FIGS. 7-10, however, has a substantiallycircular outer cross-section. Furthermore, while endoscopic forceps 10contains as part of its shaft a wound coil 14, or 14 b in FIG. 2 b,endoscopic needle 210 may or may not have a wound coil member making uppart of its outer shaft. Endoscopic needle 210, as depicted in FIGS.5-11, has no wound coil in its outer shaft 212.

Endoscopic needle device 210 has an elongate shaft 212 which is longenough to be advanced through endoscope working channels 162, 164, 166,or 168 of FIG. 4 so that proximal shaft handle 214 and proximalactuation member handle 221 remain outside of the endoscope workingchannel, similar to the position of the proximal handle 214 andactuation handle 216 of endoscope forceps 10, as shown in FIG. 3.Returning to FIG. 5, tubular shaft 212 of endoscope needle 210 is madesufficiently long so that while proximal handles 214 and 221 project outof the proximal end of a working channel such as 162, 164, 166, or 168in FIG. 4, at least distal end 218 of tubular shaft 212 will reach tothe distal end of the respective working channel at the distal end ofthe endoscope. In a representative embodiment of the present invention,tubular shaft 212 is approximately 200 cm long. Within tubular shaft212, inner control member 220 is joined at its proximal end to proximalactuation handle 221. Actuation handle 221 has at its proximal end afitting 222 for attachment of a fluid or suction source. In a preferredembodiment, this fitting 222 is a standardized fitting such as a tubularfitting.

The distal end 218 of the tubular shaft 212 and of inner control member220 is shown in a detailed longitudinal cross-section in FIG. 6. In arepresentative embodiment of the present invention, inner control member220 is tubular and has a central lumen 224. The central lumen 224extends throughout inner control member 220, thereby allowing fluidcommunication throughout control member 220, to provide a path for fluiddelivery to or suction from the distal end 226 of tubular control member220. At the distal end 226 of inner control member 220, a hollow needle228 is fitted within the inner control member. In a preferredembodiment, the hollow needle 228 has an outer diameter equal to orslightly larger than the inner diameter of control member 220 prior toplacement of needle 228 within inner control member lumen 224. To secureneedle 228 within control member lumen 224, a crimp sleeve 230 ispreferably placed around the distal end 226 of control member 226 andcrimped tightly around the tubular control member 220. In a preferredembodiment of the device, a shrink tube or painted band, not depicted,surrounds the tubular shaft of the device toward the distal tip 218 toaid in visibility of the distal end 218 of the device 210. For example,if the control member 220 and tubular shaft 212 are translucent orclear, a colored band may surround the tubular shaft 212 at its distalend 218. If the endoscopic instrument 210 is to be used in aradiographic procedure, the entire device may be opaque, for example,black. In the radiography use of the device 210, the crimp tube 230which secures needle 228 may provide a radiopaque marker of the distalend 218 of the instrument 210 in general, and of the needle 228 inparticular.

A radial cross-section of a representative embodiment of the shaft 212and control member 220 of endoscope needle device 210 of FIG. 5 isdepicted in FIG. 7. The outer shaft 212 is depicted with a substantiallycircular outer and inner cross-sectional shape, although, as previouslydiscussed, the outer surface of tubular shaft 212 may have anon-circular cross-sectional shape in order to reduce backlash betweenthe endoscopic instrument tubular shaft 220 and a smooth working channelof the endoscope, such as working channel 166 or 168 in FIG. 4. Withintubular shaft 212, the cross-sectional shape of tubular control member220 is shown to have a number of longitudinal ridge-like projections 232radiating from the central axis of the control member lumen. In apreferred embodiment, these projections 232 increase the effective outerdiameter of control member 220 to be almost equal to or equal to theinner diameter of tubular shaft 220, thus reducing backlash of thecontrol member vis-à-vis the tubular shaft, much in the same way thatbacklash may be reduced between the tubular shaft 212 and workingchannel 166 or 168, as previously discussed. For clarity ofillustration, the ridge-like longitudinal projections 232 are depictedas not touching the inner wall of the tubular shaft 212, but in apreferred embodiment, preferably a majority of the ridges will contactthe inner wall of tubular shaft 212 in order to better prevent deviceactuation backlash.

The longitudinal ridges 232 in the outer surface of the control member220 may be formed by a process of extrusion through a die that iscomplementary to the desired cross-sectional shape of the tubular shaft220 of FIG. 7. Other methods of creating the ridge projections 232 incontrol member 220 are possible, including the imparting of ridges 232by means of a jacket surrounding a central tubular control element suchas a hypotube or another tubular material. By way of example, and not bylimitation, for an endoscopic instrument intended to be inserted into anendoscope having a working channel lumen of 3.2 mm inside diameter, thetubular shaft 212 of the endoscopic instrument may have a maximum outerdiameter of approximately 2.2 mm and an inner diameter of about 1.8 mm.In such a device, the control member is preferably a member with acircular cross-section 1.2 millimeters in diameter with thin ridges (orlands) extending approximately 0.2 mm out from the control member'sgeneral outer diameter surface. Such a construction would almostcompletely fill the inner diameter of the instrument shaft of theendoscope (i.e., the radial dimension of the tubular control member 220,or tubular core of control member 220 together with ridges 232, from thecenter of the lumen 224 out to the end of a ridge 232, is nearly equalto the radius of the shaft 212 inner lumen), substantially reducing themotion backlash experienced by the operator in effecting the device endeffector assembly. However, the ridges 232 still permit fluid flow inthe remaining spaces 236 outside of the tubular control member 220.Additionally, the number of contact points and surface area of frictioncreating contact points between the fins 232 and the interior of theouter shaft 212 is minimal.

In an alternative embodiment, the ridges may extend along only a distalportion of the control member, rather than along the entire length ofthe control member. If the ridges 232 were to extend to the mostproximal portion 234 of the control member 220, and fluid flow is beingeffected through the lumen 236 between control member 220 and outertubular shaft 212, it may, in some embodiments, complicate the creationof a fluid seal against the device handle 238 where the control member220 interfaces with the control member's proximal handle 238. Such sealis not needed, however, if the only fluid flow to be effected isinjection or suction through the lumen 224 of control member 220, forexample, where the distal effector assembly 228 is a hypodermic or otherhollow needle as depicted in FIGS. 5 and 6. Since the majority of theflexing of the endoscope in an endoscopic procedure takes place at thedistal portion, where the endoscope is situated inside the patient, themajority of motion backlash results from the looseness of the controlmember 220 in the distal portion of the endoscope tubular shaft 212.Accordingly, backlash in end effector assembly operation will still besubstantially reduced even if the ridges 232 are placed on only thecorresponding distal portion of the control member 220 (for example, onthe distal 25-50 cm of a 200 cm instrument) while leaving the proximalportion (i.e., 150-175 cm) a smooth cylinder. Such a control memberwould then have greatly reduced motion backlash when the end effectorassembly is manipulated by the physician, and it would allowsubstantially unimpeded fluid flow through the tubular shaft lumen 236,while providing a more easily sealed-upon surface where the controlmember exits the tubular shaft proximal handle 238. In the alternative,if the entire length of the control member 220 is ridged, for example,by extrusion through a complementary die, a fluid seal may still beaccomplished by the use of a crimp sleeve binding the control membertube around a hypotube or similar smooth and relatively rigid tubeinserted into the lumen of the control member tube in the area oftubular shaft handle 238.

If the tubular shaft of the endoscopic instrument 210 is generallysmooth, as depicted in FIGS. 7-10, reduction of backlash in movement ofthe tubular shaft vis-à-vis the working channel may be effected byimparting to a working channel a non-circular lumen shape, as previouslydiscussed with reference to working channels 162 and 164 of FIG. 4. Forexample, the working channel of the endoscope may be supplied with aninsert having a non-circular cross-section, such as insert 180 insertedinto working channel 162.

Referring now to FIG. 8, an alternate radial cross-section along line7-7 of FIG. 6, depicting an alternate embodiment of the invention, isshown. FIG. 8 depicts a cross-sectional view of the distal end of theendoscopic device in which a non-circular cross-sectional shape isimparted to the inner surface of tubular shaft member 212 in order toreduce backlash in movement of circular shaped control member 220 duringend effector assembly operation. The non-circular shape of tubular shaftmember 212 may be imparted by compression with heat shrink tubing overan appropriately textured mandrel.

The application of heat to the tubular shaft will impress the desiredridges into the lumen of the tubular shaft. Alternatively, to impartridges into the lumen of the tubular shaft, the tubular shaft may beformed by extrusion of the desired tubular shape using a complementarydie through which the material of the tubular shaft is extruded. Thetubular shaft may be extruded from a low friction material.

The ridges 240 can be quite small. For example, the ridges 240 may beapproximately 0.2 mm thick and have a radial length of approximately 0.2mm. Therefore, the ridges would have a minimal effect on the fluid flowcross-sectional area between the working channel and the endoscopicinstrument, and also provide relatively small contact points between theworking channel and the endoscopic instrument.

FIG. 9 shows a cross-section along line 7-7 of FIG. 6 of an alternateembodiment with a control member having a non-circular outer wall andinner wall. This formation of the control member may be compared to theendoscopic device depicted in cross-section in FIG. 2 b, or toendoscopic device 108 in FIG. 4, in which an endoscopic shaft with apolygonal cross-sectional shape is disposed within a working channelwith a substantially circular cross-sectional shape. For the polygonalcross-section tubular control member, by way of example and not bylimitation, for a control member 220 intended to be in an endoscopicinstrument shaft 212 having a lumen of 1.8 mm inside diameter, thecorners 242 of a five-cornered polygon, or pentagon, preferably extendapproximately 0.8 mm from the center of the control member lumen 224.Such a construction substantially completely fills the diameter of theendoscope shaft lumen, substantially reducing the end effector assemblyactuation backlash, yet only contacts the working channel at the corners242, analogous to the relationship between polygonal endoscopic deviceshaft 106 and working channel 168 in FIG. 4. In addition, space 236 isprovided between the sides of the control member 220 and the instrumentshaft 212 lumen for fluid flow, in the same way as space is provided inworking channel 168 in FIG. 4. Other embodiments are possible, asdepicted in FIG. 10, including a control member 220 having anon-circular outer wall, with an inner wall having a substantiallycircular cross-sectional shape. For example, a polymeric jacket 244 maybe placed over a hypotube core 246 to provide a control member 220having a non-circular cross-sectional shape.

FIG. 11 depicts an alternate cross-section along line 7-7 of FIG. 6, inwhich a tubular shaft 212 provides both an outer wall with anon-circular cross-sectional shape and an inner wall with a non-circularcross-sectional shape for backlash reduction with a circular controlmember 220. This endoscopic instrument shaft reduces backlash both withregard to the movement of the entire endoscopic instrument within aworking channel, as described with regard to FIG. 4, showing endoscopicinstrument 106 within working channel 168, and further with regard tooperation of distal end effector assembly by means of control member220. As shown in FIGS. 2 b and 4, the outer wall of the endoscopicinstrument shaft 106 will contact the inner wall of working channel 168at corners 30 b.

The polygonal cross-sectional shape may be provided to the tubular shaft212 via a mandrel or core wire with complementary ridges, around whichthe tubular shaft could be placed covered with heat shrink tubing, andheated. Alternatively, the cross-sectional shape may be formed byextrusion of tubular shaft 212 through a complementary die in order toachieve a polygonal cross-sectional shape within the lumen of theinstrument tubular shaft.

In each of the alternate embodiments, the instrument's tubular shaft orcontrol member is adapted to provide reduced end effector assemblybacklash, while maintaining adequate fluid flow in the tubular shaftaround the control member, and minimal contact between the controlmember and the tubular shaft inner wall. In each alternate embodiment,the non-circular cross-sectional shape of the tubular shaft lumen orcontrol member may extend the entire length of the instrument or aportion thereof.

There have been described and illustrated herein several embodiments ofan endoscope and endoscopic instrument system having reduced backlashwhen moving the control member within the shaft lumen of the endoscopicinstrument. While particular embodiments of the invention have beendescribed, it is not intended that the invention be limited thereto, asit is intended that the invention be as broad in scope as the art willallow and that the specification be read likewise. Thus, while aparticular injection endoscopic instrument has been disclosed, it willbe appreciated that endoscopic instruments having other end effectors(e.g., forceps, scissors, punches, alternate needles, etc.) can beprovided with the non-circular cross-section of the invention as well.Furthermore, while a PTFE has been disclosed for the instrument'stubular shaft and control member, other low-friction materials can beused as well. Also, while a particular number of ridges and ribs havebeen disclosed, it will be appreciated that other numbers of ridges andribs can be used. Alternatively, one or more spiral ridges or ribs canbe provided. Furthermore, projections other than ridges can be used.Moreover, other polygonal shapes may be used for the core member andtubular shaft lumen. Also, the control member tube and the instrumentshaft tube may be substituted with another tubular member having anon-circular cross-section. It will, therefore, be appreciated by thoseskilled in the art that yet other modifications could be made to theprovided invention without deviating from its spirit and scope as soclaimed.

What is claimed is:
 1. A medical device, comprising: an endoscopeincluding an endoscope handle and a tubular member, the tubular memberhaving a length, an inner surface, a first lumen defined along at leasta portion of the length, and a second lumen defined along at least aportion of the length; a shaft slidably disposed in the first lumen, theshaft having a proximal end, a distal end, a length, and an outersurface; wherein the shaft has a substantially circular cross-sectionalshape; a non-expandable sleeve disposed along and fixed to the outersurface of the shaft; an optical scope disposed in second lumen; whereinthe sleeve has a transverse cross-sectional shape that is polygonalalong a portion of its length; wherein the tubular member has an innerdiameter and the polygonal shape of the sleeve defines a maximum outerdiameter of the sleeve that is substantially equal to the inner diameterof the tubular member; and an end effector disposed adjacent the distalend of the shaft, the end effector including a biopsy tool.
 2. Themedical device of claim 1, wherein the end effector includes a biopsyforceps or a biopsy needle.
 3. The medical device of claim 1, whereinthe inner surface of the tubular member has a non-circularcross-sectional shape along a portion of its length.
 4. The medicaldevice of claim 1, wherein the inner surface of the tubular member has asubstantially circular cross-sectional shape along its length.
 5. Amedical device, comprising: an endoscope including an endoscope handleand a tubular member, the tubular member having a length, an innersurface, a first lumen defined along at least a portion of the length,and a second lumen defined along at least a portion of the length; ashaft slidably disposed in the first lumen, the shaft having a proximalend, a distal end, a length, and an outer surface; wherein the shaft hasa substantially circular cross-sectional shape; a sleeve attached to theouter surface of the shaft; an optical scope disposed in second lumen;wherein the sleeve has a transverse cross-sectional shape that ispolygonal along a portion of its length; wherein the polygonal shape ofthe sleeve defines a maximum outer diameter that is frictionally engagedwith the tubular member so as to reduce backlash; wherein the polygonalshape of the sleeve cooperates with the first lumen to define aplurality of spaces therebetween that permit fluid flow through thetubular member; and an end effector disposed adjacent the distal end ofthe shaft, the end effector including a biopsy tool.
 6. The medicaldevice of claim 5, wherein the end effector includes a biopsy forceps ora biopsy needle.
 7. The medical device of claim 5, wherein the innersurface of the tubular member has a non-circular cross-sectional shapealong a portion of its length.
 8. The medical device of claim 5, whereinthe inner surface of the tubular member has a substantially circularcross-sectional shape along its length.
 9. A method for using a medicaldevice, comprising the steps of: providing an endoscope assembly, theendoscope assembly including: an endoscope having a working channelextending therethrough and an optical channel extending therethrough,the endoscope having a length and an inner surface, an endoscopicinstrument slidably disposed in the working channel, the endoscopicinstrument including a shaft having a proximal end, a distal end, alength, and an outer surface, wherein the shaft has a substantiallycircular cross-sectional shape; a non-expandable sleeve fixed to theouter surface of the shaft; an end effector disposed adjacent the distalend of the shaft, the end effector including a biopsy tool, a handledisposed adjacent the proximal end of the shaft, an optical scopedisposed in optical channel; wherein the sleeve has a transversecross-sectional shape that is polygonal along a portion of its length,and wherein the tubular member has an inner diameter and the polygonalshape of the sleeve defines a maximum outer diameter of the sleeve thatis substantially equal to the inner diameter of the tubular member;disposing the endoscope assembly adjacent a body orifice; advancing theendoscopic instrument through the working channel so that the endeffector is disposed within the body orifice; and rotating the endeffector with the handle.